Re: [PATCH v3 6/6] drm/msm/dsi: Improve dsi_phy_driver_probe() probe error handling

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 03/08/2022 01:37, Douglas Anderson wrote:
> The dsi_phy_driver_probe() function has a "goto fail" for no
> reason. Change it to just always return directly when it sees an
> error. Make this simpler by leveraging dev_err_probe() which is
> designed to make code like this shorter / simpler.
> 
> Signed-off-by: Douglas Anderson <dianders@chromium.org>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

Minor nit below.

> ---
> 
> Changes in v3:
> - ("Improve dsi_phy_driver_probe() probe error handling") new for v3.
> 
>   drivers/gpu/drm/msm/dsi/phy/dsi_phy.c | 74 ++++++++++-----------------
>   1 file changed, 27 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c b/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
> index 0a00f9b73fc5..57cd525de7a1 100644
> --- a/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
> +++ b/drivers/gpu/drm/msm/dsi/phy/dsi_phy.c
> @@ -621,12 +621,9 @@ static int dsi_phy_driver_probe(struct platform_device *pdev)
>   	phy->pdev = pdev;
>   
>   	phy->id = dsi_phy_get_id(phy);
> -	if (phy->id < 0) {
> -		ret = phy->id;
> -		DRM_DEV_ERROR(dev, "%s: couldn't identify PHY index, %d\n",
> -			__func__, ret);
> -		goto fail;
> -	}
> +	if (phy->id < 0)
> +		return dev_err_probe(dev, phy->id,
> +				     "Couldn't identify PHY index\n");
>   
>   	phy->regulator_ldo_mode = of_property_read_bool(dev->of_node,
>   				"qcom,dsi-phy-regulator-ldo-mode");
> @@ -634,88 +631,71 @@ static int dsi_phy_driver_probe(struct platform_device *pdev)
>   		phy->cphy_mode = (phy_type == PHY_TYPE_CPHY);
>   
>   	phy->base = msm_ioremap_size(pdev, "dsi_phy", &phy->base_size);
> -	if (IS_ERR(phy->base)) {
> -		DRM_DEV_ERROR(dev, "%s: failed to map phy base\n", __func__);
> -		ret = -ENOMEM;

Here (and in a few cases later) this changes the error code from crafted 
-ENOMEM to the proper one returned by msm_ioremap_size(). This should be 
mentioned in the commit message.

> -		goto fail;
> -	}
> +	if (IS_ERR(phy->base))
> +		return dev_err_probe(dev, PTR_ERR(phy->base),
> +				     "Failed to map phy base\n");
>   
>   	phy->pll_base = msm_ioremap_size(pdev, "dsi_pll", &phy->pll_size);
> -	if (IS_ERR(phy->pll_base)) {
> -		DRM_DEV_ERROR(&pdev->dev, "%s: failed to map pll base\n", __func__);
> -		ret = -ENOMEM;
> -		goto fail;
> -	}
> +	if (IS_ERR(phy->pll_base))
> +		return dev_err_probe(dev, PTR_ERR(phy->pll_base),
> +				     "Failed to map pll base\n");
>   
>   	if (phy->cfg->has_phy_lane) {
>   		phy->lane_base = msm_ioremap_size(pdev, "dsi_phy_lane", &phy->lane_size);
> -		if (IS_ERR(phy->lane_base)) {
> -			DRM_DEV_ERROR(&pdev->dev, "%s: failed to map phy lane base\n", __func__);
> -			ret = -ENOMEM;
> -			goto fail;
> -		}
> +		if (IS_ERR(phy->lane_base))
> +			return dev_err_probe(dev, PTR_ERR(phy->lane_base),
> +					     "Failed to map phy lane base\n");
>   	}
>   
>   	if (phy->cfg->has_phy_regulator) {
>   		phy->reg_base = msm_ioremap_size(pdev, "dsi_phy_regulator", &phy->reg_size);
> -		if (IS_ERR(phy->reg_base)) {
> -			DRM_DEV_ERROR(&pdev->dev, "%s: failed to map phy regulator base\n", __func__);
> -			ret = -ENOMEM;
> -			goto fail;
> -		}
> +		if (IS_ERR(phy->reg_base))
> +			return dev_err_probe(dev, PTR_ERR(phy->reg_base),
> +					     "Failed to map phy regulator base\n");
>   	}
>   
>   	if (phy->cfg->ops.parse_dt_properties) {
>   		ret = phy->cfg->ops.parse_dt_properties(phy);
>   		if (ret)
> -			goto fail;
> +			return ret;
>   	}
>   
>   	ret = devm_regulator_bulk_get_const(dev, phy->cfg->num_regulators,
>   					    phy->cfg->regulator_data,
>   					    &phy->supplies);
>   	if (ret)
> -		goto fail;
> +		return ret;
>   
>   	phy->ahb_clk = msm_clk_get(pdev, "iface");
> -	if (IS_ERR(phy->ahb_clk)) {
> -		DRM_DEV_ERROR(dev, "%s: Unable to get ahb clk\n", __func__);
> -		ret = PTR_ERR(phy->ahb_clk);
> -		goto fail;
> -	}
> +	if (IS_ERR(phy->ahb_clk))
> +		return dev_err_probe(dev, PTR_ERR(phy->ahb_clk),
> +				     "Unable to get ahb clk\n");
>   
>   	/* PLL init will call into clk_register which requires
>   	 * register access, so we need to enable power and ahb clock.
>   	 */
>   	ret = dsi_phy_enable_resource(phy);
>   	if (ret)
> -		goto fail;
> +		return ret;
>   
>   	if (phy->cfg->ops.pll_init) {
>   		ret = phy->cfg->ops.pll_init(phy);
> -		if (ret) {
> -			DRM_DEV_INFO(dev,
> -				"%s: pll init failed: %d, need separate pll clk driver\n",
> -				__func__, ret);
> -			goto fail;
> -		}
> +		if (ret)
> +			return dev_err_probe(dev, ret,
> +					     "PLL init failed; need separate clk driver\n");
>   	}
>   
>   	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
>   				     phy->provided_clocks);
> -	if (ret) {
> -		DRM_DEV_ERROR(dev, "%s: failed to register clk provider: %d\n", __func__, ret);
> -		goto fail;
> -	}
> +	if (ret)
> +		return dev_err_probe(dev, ret,
> +				     "Failed to register clk provider\n");
>   
>   	dsi_phy_disable_resource(phy);
>   
>   	platform_set_drvdata(pdev, phy);
>   
>   	return 0;
> -
> -fail:
> -	return ret;
>   }
>   
>   static struct platform_driver dsi_phy_platform_driver = {


-- 
With best wishes
Dmitry